I have seen a network user on a Managed Client logging in hang before the Finder and Dock load, so it just sits there with the desktop picture and only the Spotlight part of the menubar visible. The fix is simple. Delete these folders:

While deleting all caches will certainly fix the problem, the symptoms described are caused by corruption of the Apple Type Services cache so
"sudo rm -rf /Library/Caches/com.apple.ATS/"
will do the trick